In the prior art film-forming apparatus forming a film on the surface of a semiconductor wafer using a CVD device including a MOCVD device or the like, the technique of supplying a carrier gas containing film-forming liquid materials into a vaporizer and vaporizing the raw materials in the vaporizer is known.
Furthermore, with the above vaporizer, a heater is provided around the vaporizer or around the pipe through which the carrier gas is supplied into the vaporizer so as to vaporize the raw material with heat from the heater (for example, Patent Literature 1 to 3).
Furthermore, Patent Literature 4 discloses a technique of introducing liquid raw material into a carrier gas, dispersing the liquid raw material atomized to the order of a micron or smaller (1 micron or smaller) in size in the carrier gas (hereafter, a carrier gas in which liquid raw materials are dispersed is referred to as raw material gas), introducing the raw material gas into a vaporizer to vaporize the raw material, and then forming a film in the film-forming chamber. In doing so, a means for cooling the exit is provided to prevent clogging at the exit as a result of only the solvent evaporating. Furthermore, the liquid raw material is dispersed in a carrier gas as finer particles; therefore, the flow rate of the carrier gas is preferably 50 to 340 msec.
However, when a film is formed by the above technique, the film sometimes has a ripple on the surface. Furthermore, the presence of particles in the film or on its surface is observed. Furthermore, the film sometimes has a composition deviated from the target composition. Furthermore, the presence of particles in the film or on its surface is observed. Furthermore, the film sometimes has a composition deviated from the target composition. Furthermore, an increased content of carbon is sometimes observed.
FIG. 6 is an illustration of a prior art vaporizer disclosed in FIG. 15 of Patent Literature 4. The vaporizer is formed by sequentially connecting the body of a dispersion unit 8, a connection unit 23, and a vaporization unit 22.